1. Field of the Invention
The present invention relates to a solid-state image pickup device, a method of manufacturing a solid-state image pickup device, and an electronic apparatus. More specifically, the invention relates to a solid-state image pickup device, a method of manufacturing a solid-state image pickup device, and an electronic apparatus in which deposition of dust on an optical path during the manufacture of the device or apparatus is prevented.
2. Description of the Related Art
There has been disclosed a technology in which a flattening film lower in refractive index than microlenses of a solid-state image pickup element is disposed on the microlenses, and the flattening film is used as a protective film to thereby prevent deposition of dust and to provide hermetic seal between the solid-state image pickup element and a transparent substrate, thereby reducing reflection at interfaces and increasing the sensitivity of the image pickup element.
For example, Japanese Patent Laid-Open No. Hei 6-232379 referred to as Patent Document 1 hereinafter describes a configuration in which a transparent flat film having water repellency and oil repellency is provided at an outermost layer of a solid-state image pickup element. It is shown that this configuration enables easy cleaning of dust or the like deposited on the outermost layer of the solid-state image pickup element. It is also shown that the transparent flat film has a low surface energy, so that contamination with dust or the like is suppressed.
Besides, Japanese Patent Laid-Open No. 2007-53153 referred to as Patent Document 2 hereinfater describes a configuration in which a flat layer of a fluoro acrylic resin is formed on microlenses of a solid-state image pickup element, and the surface of the flat layer is roughened. It is shown that by this configuration it is possible to reduce or obviate deposition of dust or foreign matter during later steps such as dicing or module fabrication.
Furthermore, Japanese Patent Laid-Open No. 2007-53324 referred to as Patent Document 3 hereinafter describes a structure of a solid-state image pickup element in which a fluorine-containing resin material layer is provided on microlenses of the image pickup element, a resin layer is provided over the fluorine-containing resin material layer, and a transparent substrate is disposed over the resin layer. It is shown that this structure makes it possible, by appropriately determining the refractive indexes of the layers, to reduce reflected components of the light incident on the solid-state image pickup element, and promises an increased sensor sensitivity. It is also shown that, by eliminating an air layer between the solid-state image pickup element and the transparent substrate, deposition of dust or the like during transportation of a solid-state image pickup device is prevented.